
public class MinDistance {
    public int minDistance(String word1, String word2) {
        int len1 = word1.length(), len2 = word2.length();
        int dp[][] = new int[len1 + 1][len2 + 1];
        for (int i = 1; i <= len1; i++) {
            dp[i][0] = i;
        }
        for (int i = 0; i <= len2; i++) {
            dp[0][i] = i;
        }

        for (int i = 1; i <= len1; i++) {
            for (int j = 1; j <= len2; j++) {
                if(word1.charAt(i-1)==word2.charAt(j-1)){
                    dp[i][j]=dp[i-1][j-1];
                }else{
                    dp[i][j]=min(dp[i-1][j]+1,dp[i-1][j-1]+1,dp[i][j-1]+1);
                }
            }
        }
        return dp[len1][len2];


    }

    private int min(int a, int b, int c) {
        return Math.min(a,Math.min(b,c));
    }


}
